<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8">
    <title>设置字体的粗细</title>
    <style>
        p.normal {
            font-weight: normal;
        }

        p.light {
            font-weight: lighter;
        }

        p.thick {
            font-weight: bold;
        }

        p.thicker {
            font-weight: 900;
        }
    </style>
</head>

<body>
    <p class="normal">This is a paragraph.</p>
    <p class="light">This is a paragraph.</p>
    <p class="thick">This is a paragraph.</p>
    <p class="thicker">This is a paragraph.</p>
</body>

</html>